螺杆泵在段塞流工况下的优势

I. Causes of Slug Flow

1. Gas – Liquid Velocity Difference：Gas often flows faster. It can push liquid into large slugs, triggering slug flow.
2. Pipeline Geometric Factors：Bends, diameter changes, and inclination in pipelines affect gas – liquid flow, causing slug flow.
3. Gas – Liquid Ratio：When the ratio is in a certain range, slug flow is likely.
4. Fluid Physical Properties：Liquid’s viscosity, surface tension, and gas’s density, viscosity affect the gas – liquid interface, potentially leading to slug flow.
5. Flow Interference：Obstacles in pipelines or valve throttling can change flow, inducing slug flow.

II. Types of Oil Wells Prone to Slug Flow in Oilfields

1. High Gas – Liquid Ratio Oil Wells：These wells have a high gas – liquid ratio. Fast – flowing gas can form slug flow while pushing liquid. For example, in late – stage oil wells, more gas escapes, increasing the ratio and causing frequent slug flow.
2. Oil Wells in Complex Terrain Areas：In mountainous or offshore areas, pipelines may have many bends, undulations, or diameter changes. Gas – liquid flow through these structures promotes slug flow. Offshore subsea pipelines are a good example.
3. Low – Permeability Reservoir Oil Wells：Low – permeability reservoirs cause poor fluid flow. Gas – liquid flow interference in these wells can lead to slug flow, affecting production.

III. Performance of Different Pumps under Slug Flow Conditions

Performance Advantages of Twin – Screw Multiphase Pumps in Slug Flow

1. Excellent Gas – Liquid Mixing Handling Capacity：The screws and bushings form sealed chambers. These can handle gas – liquid mixtures well. Even with a changing gas – liquid ratio in slug flow, they maintain continuous transportation. Gear and vane pumps struggle with gas – liquid mixing and may block.
2. Minimal Pressure Pulsation：Slug flow makes pressure unstable. Twin – screw multiphase pumps have little pressure pulsation. This protects pipelines and equipment. Diaphragm pumps, however, have large pulsations.
3. High Operational Stability：Twin – screw multiphase pumps have a simple design with few moving parts. They stay stable in slug flow, rarely shutting down due to component failure. Complex – structured pumps like some piston pumps are more likely to malfunction.
4. Good Medium Inclusiveness：Oilfield fluids may have impurities. Twin – screw multiphase pumps can handle impure media well, without getting stuck. Precision – structured pumps like metering pumps may be affected.
5. Low Maintenance Cost：Twin – screw multiphase pumps wear less in slug flow. Their long – term stability means a longer maintenance cycle and lower cost. Gear and vane pumps wear more, increasing maintenance and downtime.